1. Field of the Invention
The present invention relates to a circuit for testing a display device to detect any fault therein.
2. Description of the Prior Art
It has been known heretofore that, for the purpose of detecting the presence or absence of any fault in a CRT display device when no video signal is supplied from a computer, a test is conducted to brighten the CRT by either lowering a cathode voltage to the CRT or raising a first grid voltage therein.
The above prior art technique is effective for checking if a deflector and a power supply in the display device are normal or not. However, it is not exactly effective for testing a video amplifier which is incorporated to amplify a video signal. Although there is available an improved display device of a type including a signal generator to test a video amplifier, a problem of high production cost is unavoidable.